To EGR or not to EGR..

[Steve Vague]

..that is the question. Actually, to be more specific, I am trying to determine whether a non EGR equiped motor will be measurably (per emissions tail pipe test) cleaner than EGR equiped. From all I have been able to determine the EGR is only effective at higher operating combustion temperatures. I would therefore assume, this would be at higher loads or RPM than are typical in an emissions test. I am changing induction and prefer to install a non EGR manifold if it can pass the sniff test. Can any one shed light on this?
Thanks in advance,
Steve

[Excaliber]

Your on the right track. The EGR keeps the peak combustion down, thus limiting NOX emissions. Depends on the kind of test they will run on the car. If it's a "load test" you WILL fail. If it's just a standard sniffer test, the question remains: Will you pass without it? NOX is directly linked to high combustion temps and is one of the primary things they look for in a smog test. Retarding your timing just for the test may be the solution if you don't have an EGR. But I would be surprised if the "tech" didn't spot the fact that you DON'T have one and fail you for that without even running a test.

EGR WILL decrease performance.

Ernie

[Jack21]

If your car requires emissions, save the original carb and intake. If your non-EGR flunks, bolt the original back on for the test, then take it back off again for driving. This is what we had to do to our '70's cars. Keep an emissions test parts box or shelf and perform this ritual every year.